[Evaluation of renal transplant function by 99mTc-DTPA dynamic imaging (author's transl)]

In 60 patients with a kidney transplant 86 perfusion studies with 99mTc-DTPA were performed during the early postoperative period. Correlative data and clinical differentiation were obtained by isotope nephrograms, laboratory values and clinical presentation. In addition to evaluation of scintiphotos, time-activity curves were derived from the transplant and evaluated quantitatively, obtaining a perfusion ratio by a computer program. A ratio of greater than 0.80 was found to be normal. In 20 patients with acute rejection, the ratio was decreased. In 13 patients with acute tubular necrosis, the perfusion ratio was between 0.39 and 0.65, decreasing further during an added rejection crisis. Follow-up examinations confirmed rejection through a decrease of the perfusion ratio (mean difference 0.44; p less than 0.025). In 9 cases, successful rejection therapy was documented by an increase (mean difference 0.29; p less than 0.005). In addition to quantitative evaluation, visual analysis revealed acute occlusion of the renal artery, renal infarction, urinoma, ureteral stenosis or necrosis. Quantitative scintigraphy with 99mTc-DTPA broadened the methods of describing kidney transplant function. Its quantitative evaluation enables the definition of acute rejection and its differentiation from acute tubular necrosis combined with acute rejection in the early postoperative period. Since the method recognizes morphological alterations as well, it usefully complements isotope nephrography.